'Night Owl' Lifestyle Raises Odds For Diabetes If You're Obese

"The sleep-wake cycle is one of the most important behavioral rhythms in humans," said lead researcher Dr. Giovanna Muscogiuri. She is an assistant professor in the endocrinology unit of the University of Naples Federico II, in Italy

This study compared the sleep patterns and disease in 172 middle-aged people as part of an ongoing obesity prevention study in Italy in which participants were grouped according to sleep patterns. 6 in 10 of the participants were morning lark early risers who tend to wake up and be most active in the early day, 13% were night owls who tend to wake up late and be most active during late afternoon/evening, and 3 in 10 were intermediate types falling somewhere in between.  

All 3 groups had similar BMIs, however, the night owl group was more likely to eat big dinners and have other unhealthy habits like lack of physical exercise and tobacco use which put them at a higher risk for health problems. 

30% of the morning larks and 55% of the night owls had heart disease. The risk of diabetes was 9% among the morning larks and 37% among the night owls, with there being no difference between the intermediate group and the morning lark group. 

Previous research estimated that night owls have 1.3 times the risk of high blood pressure and high cholesterol compared to morning larks. Night owls are also less likely to follow a heart-friendly diet such as a Medierranenan style diet that is rich in vegetables, fruits, and fish. The preliminary findings of this study were presented at a virtual meeting of the European Congress on Obesity. 

When taken together, Muscogiuri says that all these features contribute to night owls being at higher risk for heart disease and type 2 diabetes. She also suggests that the best efforts to combat obesity might be more successful if sleep patterns were taken into account. AS she explains, the idea would be to help those who are obese develop better sleep-wake habits based on earlier rising, because those patterns might help to develop better dietary and activity habits thereby “Increase their chance of success for weight loss.”

But getting people to change their lifestyle habits/choices such as eating, sleeping, and activity routines may not be an easy task, says cardiologist Dr. Kenneth Ellenbogen, of the Medical College of Virginia, in Richmond:

"We know how hard it can be to reset an individual's biological clock or activity habits," he said. "And while this is certainly fascinating work, it's really hard to know what's really going on from one observational study involving a relatively small number of patients."

Ellenbogen also notes that it is unclear whether sleeping in is a direct cause of the increased risks or whether it is the lifestyle associated with sleeping in that indirectly increases the risks. "It's not at all obvious to me what the answer is," he said after reviewing the findings. "And I certainly wouldn't say this study proves anything like cause and effect."